1. Field of the Invention
The present invention relates to the operation of a closure normally operated by a motor and, more particularly, to an auxiliary device for allowing manual operation of the closure.
2. Description of the Prior Art
It is well known in the art of closures operated by way of electric motors to provide each system with an auxiliary operating device to permit manual operation of the closure in the event, for instance, of a failure of the electric motor.
Canadian Patent Application No. 2,112,350 filed on Dec. 23, 1993 in the name of Manaras et al. and laid-open on Jun. 24, 1995 discloses such an auxiliary closure operating device which is mounted on a motor driving an output shaft adapted to open and close a closure, such as a garage door. The auxiliary operating device comprises a shaft mounted for rotational and axial movements within an elongated surrounding sleeve supported on the motor. A first gear is mounted at a first end of the shaft for rotation therewith. In its idle position, the first gear is engaged by a locking finger in order to prevent rotational movement of the shaft. A pulley is mounted for free rotation at the opposed end of the shaft and is engaged with a manual chain. A disc is mounted to the hub of the pulley for engaging a cam member fixedly mounted to the shaft adjacent the pulley. The initial rotational movement induced to the pulley via the manual operation of the chain causes the disc to displace along the cam member so as to push the latter away from the pulley, thereby causing the shaft, which is locked against rotation due to the engagement of the locking finger with the first gear, to slide axially within the sleeve. At one point, the first gear will disengage from the locking finger and will mesh with a second gear secured to the output shaft, thereby allowing the shaft to rotate with the cam member in order to drive the output shaft. At the same time, the disc will engage a stopper on the cam member such that further rotation of the pulley will be transmitted as a torque to the cam member, thereby causing the rotation of the shaft and of the first gear and, thus, of the second gear and of the motor""s output shaft.
Although the auxiliary closure operating device described in the above mentioned Patent Application is effective, it has been found that there is a need for a new auxiliary closure operating device which is more compact and which involves fewer or simpler interacting parts.
It is therefore an aim of the present invention to provide a new closure operating device which can be manually operated to displace a closure which is normally driven by a motor.
It is also an aim of the present invention to provide a closure operating device which is relatively compact.
It is a further aim of the present invention to provide a closure operating device which is relatively simple and economical to manufacture.
It is a still further aim of the present invention to provide a limit switch mechanism having an access door which is adapted to stay open and
It is a still further aim of the present invention to provide a closure door operator casing which is configured to facilitate access to the components housed therein.
Therefore, in accordance with the present invention, there is provided an auxiliary operating device for manually operating an output shaft normally driven by a motor in order to displace a closure between open and closed positions. The device comprises a manual actuator, and a driving member freely mounted on the output shaft and axially displaceable therealong between a first axial position in which the driving member and the output shaft are independently rotatable relative to one another and a second axial position in which the driving member is engaged with the output shaft and the manual actuator to transmit a torque from the manual actuator to the output shaft.
In accordance with a further general aspect of the present invention, there is provided a limit switch mechanism for controlling the operation of a motor over a selected range of movement, comprising a casing, a motor driven threaded shaft journaled to the casing, at least one switch actuator threadably engaged on the threaded shaft and adjustably positionable thereon, a limit switch mounted to the casing adjacent the threaded shaft so as to be actuated by the switch actuator when the same reaches a predetermined position on the threaded shaft, an access plate pivotally mounted to the casing for movement between closed and open positions, wherein in the closed position the access plate is engaged with the switch actuator to prevent rotation of the switch actuator while allowing axial movement thereof along the threaded shaft as a result of the threaded shaft, and biasing means connected to the access plate adapted to urge the access plate towards the closed position when the access plate is within a first range of positions and towards the open position when the access plate is within a second range of positions distinct from the first range.
In accordance with a further general aspect of the present invention there is provided a casing for housing components of a closure operating device, comprising a back wall adapted to be mounted on a mounting surface, outer wall means extending forwardly from the back wall to define an interior space therewith, the outer wall means having at least a forward portion thereof which extends at an obtuse angle with respect to the back wall. The forward portion has an inner surface on which various components can be mounted, whereby accessibility to the components mounted to the inner surface is facilitated due to the orientation of the forward portion with respect to the back wall.